Monsignor is an ecclesiastical honorific for clergy of the Roman Catholic Church. The word comes from the French Mon Seigneur, meaning "my lord". In English, it is abbreviated Mgr., Msgr. or Mons.

In some European languages Monsignor (or its equivalent) is the simple style for bishops (including archbishops) who are not cardinals, as opposed to the formal style of Excellency. In English-speaking countries, however, apart from those where Catholics have been strongly influenced by one of those other languages, the title of Monsignor is not given to bishops, but only to those priests who have been included

• Apostolic Protonotaries (the highest and least common form)
• Honorary Prelates of His Holiness (formerly "Domestic Prelate")
• Chaplains of His Holiness (formerly "Papal Chamberlain")

The changes of denomination were brought about by Pope Paul VI's motu proprio Pontificalis Domus of 28 March 1968. One year later, an Instruction of the Secretariat of State simplified the dress and the forms of address.

Before these reforms, Papal Chamberlains were called "Very Reverend Monsignor" and the higher ranks "Right Reverend Monsignor". This was simplified to prescribe for all the form "Reverend Monsignor", often reduced simply to "Monsignor".

Papal Chamberlains used to be appointed only for the lifetime of the Pope, so that the appointment had to be obtained anew from his successor. This distinction too was eliminated by

Chaplains of His Holiness may use a purple-trimmed black cassock with purple sash. The trimming and buttons of the black cassock of Honorary Prelates differs from those of Chaplains of His Holiness in being of the same shade of red as those of bishops. They use a purple cassock as their choir dress.

Apostolic Protonotaries can be numerary or supernumerary. The former are very few, usually seven, who have an actual function to perform in the direct service of the Pope. Appointment as an Apostolic Protonotaries Supernumerary is simply the award of a title with certain privileges. Their dress is the same as for Honorary Prelates except that they have the option of also using a purple ferraiuolo or cape. In English-speaking countries, they sometimes add the letters, "P.A." (for Protonotarius Apostolicus) after their names.

Vicars General have the rank of Apostolic Protonotary durante munere and are therefore styled Monsignor as long as they hold that office. Episcopal Vicars are often accorded the same title on less certain grounds.

References

• Heim, Bruno Bernard. Heraldry in the Catholic Church: Its Origins, Customs, and Laws. New Jersey: Humanities Pres Inc, 1978. ISBN 0-391-00873-0.
• Paul VI. "On the Papal Household." On the Papal Household, Reform of the Use of Pontifical Insignia, Simplification of Pontifical Rites and Insignia. Washington, DC: United States Catholic Conference, 1968.
• "Instruction on the dress, titles and coat-of-arms of cardinals, bishops and lesser prelates." L'Osservatore Romano, English ed. 17 Apr. 1969: 4. ISSN 0391-668X. Online at Monsignore

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